I'm not really sure it qualifies as a tactic, just a routine developing move hitting the Rook on a2 and the pawn on b5. As to whether the pawn on b5 should be taken, that requires a bit of calculation and judgement of the resulting position, since it looks possible for Black to attempt to regain the pawn with .. Rb8. If the pawn cannot be regained, White would just be winning eventually with the two connected passed pawns.

Purely counting the material, White is a piece down. Presumably it can be won back with some tactical line. Qg8 is mate if the Black Queen can be distracted. Perhaps the solution is Rg1 to pin the Bishop followed up with Bd5.